SUPERTECH exhaust valve stem seals Honda B18A B18B B20 D16A1 D16A9 ZC

Honda engines concerned

These seals equip the 6.6 mm stem exhaust valves of Honda 16-valve four-cylinders without VTEC: D16A1 and D16A9 in the Civic, CRX and Concerto, ZC in Japanese-market Integra and Civic models, B18A and B18B in the Integra, Civic, Domani and Orthia, B20B and B20Z in the CR-V, Stepwgn and S-MX, not forgetting the Acura Integra 1.6 and 1.8.

On the exhaust side each head holds 8 valves, two per cylinder. Seated on the guide, the original seal blocks the top-end oil while still greasing the stem; Honda supplies it under two numbers, 12210-PT2-004 (seal A) and 12211-PT2-004 (seal B), 8 of each.

SUPERTECH exhaust valve stem seals

Exhaust-side, the stem seal works right beside the hottest valve of the whole head. Should it crack or lose its suppleness, oil runs along the stem towards the combustion chamber and burns there: dropping level, blue smoke, carbon build-up on valve heads and inside the manifold. It must still let a trace of oil pass, without which stem and guide would wear.

For the exhaust, SUPERTECH relies on Viton (FKM), a compound picked for its long life next to hot valves; the brand presents it as built for high temperatures and quotes 204 °C (400 °F) continuous. These seals suit a guide measuring 12 mm across the outside and a 6.6 mm stem. The 8 pieces fill the exhaust side of one head; the polyacrylate (ACM) intake seals form a separate set.

Stem seal technical specifications

Stem seal installation

Technical guide

The brand offered

Working out of San Jose in California, SUPERTECH has spent over 30 years producing valves, springs, guides and valve stem seals for motorsport. Each new design is checked by finite element calculation before being tested on track alongside experienced tuners.

Why two different materials?

Intake and exhaust seals measure the same, yet the exhaust valve climbs much higher in temperature. SUPERTECH therefore fits the tougher VS-H6.6-E Viton (FKM) there and keeps VS-H6.6-I polyacrylate (ACM) for the intake. These Honda heads need 8 of each.

When valve stem seals must be replaced

• Oil disappearing, blue exhaust smoke
• Valves out or head rebuilt
• Valve guides being renewed
• Uprated valves or springs fitted

Vehicle compatibility

Honda

Acura

OEM part number (Honda B18A, B18B, B20, D16A9 stem seals): 12210-PT2-004 (seal A) and 12211-PT2-004 (seal B), 8 of each; Arai equivalents 12210-PT2-003 and 12211-PT2-003. D16A9 from 1988 to 1993 and 1991 B18A2: 12210-PM7-004 and 12211-PH7-004 (Arai 12210-PM7-003 and 12211-PH7-003).

Remember the inlet valve stem seals

Swap the intake seals in the same operation, since they work in this very head. SUPERTECH offers them for these engines: